&#34;long pot-life&#34; soya flour/cs2 glue substantially free of carbon bisulfide thickening



United States Patent 3,206,321 LONG POT-LIFE SOYA FLOUR/CS GLUE SUB- STANTIALLY FREE OF CARBON BISULFIDE THICKENING Glenn Davidson, Aurora, Ill.; Edna D. Davidson, executrix of said Glenn Davidson, deceased, assignor to Edna D. Davidson, Aurora, Ill.

No Drawing. Filed Oct. 30, 1963, Ser. No. 320,002 5 Claims. (Cl. 106--154) This application is a continuation-in-part as to common subject matter, of copending' application Serial #134,123 filed August 28, 1961, which is a continuation in part of Ser. #813,330 filed May 15, 1959, which in turn is a continuation in part of Ser. #673,179 filed July 22, 1957, which in turn is a continuation in part of Ser. #430,739 filed May 18, 1954, all of which are now abandoned.

This invention relates to a method of formulating soya flour/CS glues in a manner which avoids excessive car-. bon bisulfide thickening and the alkaline hydrolysis which has been used in the prior art to counteract carbon bisulfide thickening.

The result is a soya flour/CS glue possessing a useful plot-life many times that of any prior art soya flour/CS glue.

First, specifically I have. discovered that if a soya flour/CS glue is dispersed with an alkaline earth hydroxide, commonly commercially calcium hydroxide in the Y absence of hydroxides of the alkali metals, carbon bisul fide thickening is either nearly totally avoided or reduced to a negligible level, as long as the temperature is held below about 100 F.

The following preferred composition has remained at substantially constant viscosity and retained its full bonding strength as measured by laminating chip-boardWto form solid fiber stock for use in paper cartons,in excess of two weeks.

Parts Water (70 F.) '650' Calcium carbonate (extender) 100 Soya fiour (54% protein) 200 CS 2 /2 Calcium hydroxide All parts by weight. Ingredients combined in the order listed under power agitation. The agitation continued forone hour after the addition of the last ingredient. perature maintained below about 100 F. 1 a

Second, I have discovered that the hydroxides of the alkali metals may be incorporated into the above composition without greatly changing its general characteristics beneficially or otherwise provided the amount of such alkali metal hydroxides does not exceed the equivalent of 3.70 parts sodium hydroxide per 100 parts'of protein contained in the soya flour and still provide a minium of 12 hours useful pot life with some margin of safety.

This corresponds to approximately 2.0 parts sodium hydroxide per 100 parts soya flour containing 54% pro- Tem- 3,206,321 Patented Sept. 14, 1965 ice are patents refers to Philadelphia Quartz N Brand sodium silicate or its commercial equivalent (see line 13, col. 3, Golick #2,612,455).

According to the manufacturers specification N Brand sodium silicate contains 8.9% Na O. This is converted to NaOH by multiplying by /62. Thus, in the presence of calcium hydroxide, each 10 parts of sodium silicate yields approximately 1.15 parts of double decomposition sodium hydroxide. Similarly, 10 partssodium carbonate (Na CO yield approximately 7.5 parts NaOH and 10 parts trisodium phosphate (Na PO 121-1 0) yield approximately 3.16 parts NaOH.

The question arises as to how great an extension of the conventional 4 hr. pot life is required to be useful in a practical sense. If the laminating plant is operating 3 eight hour shifts, then the 4 hr. pot life is' reasonably adequate except perhaps at week ends.

If the plant is operating only two 8 hr. shifts in each 24 hrs., thena pot life of about 12 hrs. make it possible to use glue prepared near the end of the second shift on one day, during the first shift of the next day.

In-the case ofa plant operating only one 8 hr. shift, a

pot-life of 20-24 hrs. would make it possible to hold prepared glue from one'dayto the next.

In order to hold prepared glue over a week end, a pot life of the order'of 70 hrs. is needed.

The practical upper limit for calcium hydroxide is about parts calcium hydroxide per 100 parts soya flour protein, This upper limit is set by the fact that all commercial calcium hydroxide is more or less abrasive. All commercial laminated assemblies have to be'trimmed or otherwise machined by means of saws, disc cutters, die cutters,

clippers and the like. At calcium hydroxide contents in the glue in excess of about 100. parts calcium hydroxide per 100 parts soya flour protein (i.e. about.50 parts calcium hydroxide per 100 parts soya flour) the abrasive action on cutting tools becomes prohibitive.v

v In the case wherealkali metal hydroxides are omitted the minimum calcium hydroxide'required is in the range of 7 to 99 /2 parts per 100 parts of protein contained in.

the soya flour. The former amount is applicable only in isolated cases where neither near maximum water resistance nor pot life is required.

Alkali metal hydroxides may be used to replace a part of the minimum calcium hydroxide required, provided the total amount of such hydroxides does not exceed the above specified maximum of the equivalent of 3.70 parts sodium hydroxide per 100 parts of protein contained in the soya flour.

To illustrate: Since sodium and calcium hydroxides are approximately molecularly equivalent, sodium hydroxide may be substituted gram of gram for calcium hydroxide. -In the extreme case, the minimum total hydroxide of 7' parts per 100 parts of the protein contained in the soya flour may be made up of 3.70 parts of sodium hydroxide plus 3.30 parts calcium hydroxide. It is to be noted that this extreme case does not represent the optimum but only a formulation that can be used in isolated cases.

By isolated cases is meant, in part, the cases where the water resistance requirements are not extremely severe. Due to the minimal 3.30 parts per 100 parts soya flour protein proportion of calcium hydroxide, the water resistance might be considered to be marginal by some users for some purposes.

Also, in the presence of even small amounts of NaOH, slow carbon bisulfide thickening occurs. The rate of this thickening is somewhat dependent upon the room temperature at which the prepared glue is held, assuming no artificial cooling of the glue. At room temperatures of 90-100 F., the thickening rate is faster than at a room temperature of 70 P.

All factors including simplicity considered the optimum I claim:

1. A water-resistant adhesive, fluid at below 100 F having a usable pot life of at least 12 hours, said adhesive consisting essentially of soya flour, water, carbon bisulis represented in the case where the alkali metal hydrox- 5 fide in an amount ranging from 0.5 to 12 parts by weight idesare omitted and an alkaline earth hydroxide content for each 100 parts of soya flour protein, and an agent equivalent to 9-9.5 parts calcium hydroxide per v100 parts selected from the group consisting of (1) an alkaline earth of protein contained in the soya flour is used. metal hydroxide of from 7 to 100 parts by Weight per 100 In other words, alkali metal hydroxides are permissiparts of soya flour protein and (2) a mixture of alkaline ble up to a point, but in no sense are they essential in- 10 earth metal hydroxide and alkali metal hydroxide of from gredients ofmy new long pot-life glue. 7 to 100 parts by weight per 100 parts of soya flour pro- Magnesium, barium and strontium hydroxides are equivtein wherein the maximum alkali metal hydroxide conalents of calcium hydroxide on a molecular basis. tent is 3.70 parts by weight per 100 parts of soya flour The amounts of carbon bisulfide required range from protein. about 0.5 to 12.0 parts by weight per 100 parts protein 5 2. An adhesive according to claim 1 wherein said agent contained in the soya flour. i (1) is an alkaline earth metal hydroxide in an amount So-called inert extenders may be used, including clay, from 9 to 22 parts by weight per 100 parts of soya flour barytes, calcium carbonate, calcium sulfate, plaster of protein. Paris, asphalt, emulsions of asphalt, or various resins, 3. An adhesive according to claim 2 in which said agent rubber latex, etc; in amounts sometimes as large as sevconsists of calcium hydroxide. eral times the weight of the soya flour. 4. An adhesive according to claim 1 in which said agent The following table illustrates a number of formula- ('2) consists of a mixture of calcium hydroxide and $0 tions in which the present invention may be used. dium hydroxide.

Water-resistant as used herein means: Compliance v 5. An adhesive according to claim 1 additionally conwith Joint Army-Navy Specification Jan-P-108. 25 taining an extender.

Table All parts by weight Example Number soya Flour I Calcium Water (approx. Calcium Water Carbon Asphalt Carbonate Sodium Latex e.g. 54% Hydroxide Bisulfide or Clay or Hydroxide Dow 512-K protein) Barytes These amounts of NaOH correspond to 3.70 parts per 100 parts soya flour protein on a soya flour containing 54% protein. If a soya flour of lower protein content is-used these amounts must be correspondingly reduced. For example, soya flour containing 45% protein permits only 1.665 NaOH per 100 parts soya flour as a maximum.

References Cited by the Examiner UNITED STATES PATENTS 1,950,060 3/34 Osgood 106-l54 2,150,175 3/39 Laucks et al. 106l54 2,597,006 5/52 Koenig et a1 106l54 2,612,455 9/52 Golick 106l54 ALFRED L. LEAVITT, Primary Examiner. MORRIS LIEBMAN, ALEXANDER BRODMER- KEL, Examiners, 

1. A WATER-RESISTANT ADHESIVE, FLUID AT BELOW 100*F., HAVING A USABLE POT LIFE OF AT LEAST 12 HOURS, SAID ADHESIVE CONSISTING ESSENTIALLY OF SOYA FLOUR, WATER, CARBON BISULFIDE IN AN AMOUNT RANGING FROM 0.5 TO 12 PARTS BY WEIGHT FOR EACH 100 PARTS OF SOYA FLOUR PROTEIN, AND AN AGENT SELECTED FROM THE GROUP CONSISTING OF (1) AN ALKALINE EARTH METAL HYDROXIDE OF FROM 7 TO 100 PARTS BY WEIGHT PER 100 PARTS OF SOYA FLOUR PROTEIN AND (2) A MIXTURE OF ALKALINE EARTH METAL HYDROXIDE AND ALKALI METAL HYDROXIDE OF FROM 7 TO 100 PARTS BY WEIGHT PER 100 PARTS OF SOYA FLOUR PROTEIN WHEREIN THE MAXIMUM ALKALI METAL HYDROXIDE CONTENT IS 3.70 PARTS BY WEIGHT PER 100 PARTS OF SOYA FLOUR PROTEIN. 